Buttonhole sewing mechanism in zigzag sewing machines



June 16, I964 TOSHIO FUJlTA 3,137,256

BUTTONHOLE SEWING MECHANISM IN ZIGZAG SEWING MACHINES Fiful.

INVENTOR.

June 16, 1964 Tosl-no FUJITA 3,137,256

BUTTONHOLE SEWING MECHANISM IN ZIGZAG szwmc MACHINES Filed Aug. 28, 19612 Sheets-Sheet 2 INVENTOR.

. 3,137,256 BUTTONHOLE SEWING MECHANISM IN ZIGZAG SEWING MACHINES ToshioFujita, Morigu chi, Osaka-Eu, Japan, assignor to Sanwa Mishin SeizoKabushiki Kaisha (Sanwa Sewing Machine Mfg. Co., Ltd.), Kawachi,Osaka-tn, Japan. Filed Aug. 28, 1961, Ser. No. 134,357 4 Claims. (Cl.112-158) United States Patent 3,137,256 Patented June 16, 1964 cam orcam unit for adjusting the amplitude of the swinging movement of theneedle to produce ornamental seams.

FIGURE 8 represents diagrammatically a seam line formed on the left-handside of a buttonhole. 7

FIGURE 9 represents diagrammatically a seam line formed on theright-hand side of the buttonhole.

All of the drawings illustrate only those elements and devices which areessential to my improved mechanism and other component elements of azigzag sewing machine not related to the present mechanism are omittedfrom in conventional zigzag sewing machines and, similarly,

buttonhole, from the outer line of a zigzag seam on one side of thebuttonhole to the outer line of a zigzag seam on the opposite side ofthe buttonhole automatically, connecting the upper and lower ends ofseam lines on both sides of the buttonhole rigidly and reasonably bymeans of the so-called barring stitches.

Another object of this invention is to provide a unique buttonholesewing mechanism so devised that barring stitches at the upper and lowerends of t a buttonhole are effected in odd numbers, whereby the needleis made to return to its initial position upon completing thelast stitchin a buttonhole sewing operation, so that the same operation may berepeated over and over again.

In order to permit zigzag sewing machines to perform the aforesaidbuttonhole sewing operation incorporating the formation of perfectbarring stitches in odd numbers at the upper and lower ends of abuttonhole, a unique cam member for formingbarring stitches (hereinafterreferred to as a barring-stitch forming cam) the periphery of whichcomprises a raised portion to swing cam follower means outwardly foreach half rotation of the barring-stitch forming cam, a recessed portionto swing the said cam follower inwardly for each half rotation of thecam and several protrusions and recessions provided at the edges of theraised and lower portions to swing the said cam follower odd times, isprovided. The said barring-stitch forming cam is mounted loosely on acam shaft driven by a main shaft and is operably connected by a clutchmember with a master cam mounted on the same cam shaft'to transmit thevarious motions'of the master cam and the barring-stitch forming cam,either singly or in combination, to the needle bar.

In order that the mechanism of my invention may be clearly understood, Ishall now describe in detail the nature of my invention with referenceto the accompanying drawings, forming a part of the present applicationand illustrating the new devices and arrangements. In the drawings:

FIGURE 1 represents a front elevation, partly in sec.- tion, of a zigzagsewing machine incorporating my improved mechanism for buttonholesewing.

FIGURE 2 represents a plan view of the component elements of ,myimproved mechanism shown in FIG. 1. FIGURE 3 represents a sectional viewof the mechanism, as taken on the section line III--III of FIG. 1.

. FIGURE 4 represents a sectional view of the; same mechanism, as takenon the section line IV--IV of FIG. 1.

FIGURE 5 represents a sectional view of the same mechanism, as taken onthe section line VV of FIG. 1.

FIGURE 6 represents a perspective View of a new device forbarring-stitch formation.

FIGURE 7 represents a perspective view of a part of a regulator 32.

the drawings. The same reference characters refer to the same partsthroughout the drawings. I

The bracket-arm 1, hollow standard 2 and bed plate 3 are of the sameshapes and constructions as those used other component elements mountedinside thoseparts, such as a main shaft 4, a needle bar 5, a presser bar6, a means for moving a shuttle in time with the zigzag movement of theneedle bar, are the same as for conventional zigzag sewing machines.

Now, mounted on a cam shaft 9 which is driven by the main shaft 4 bymeans of engagement of a worm 7 of the main shaft with a worm wheel 8 ofthe cam shaft 9 are three cams of diiferent shapes and types, namely, abarring-stitch forming cam 10, a cam unit 17 for adjusting the amplitudeof the swinging movement of the needle to produce ornamental seams(hereinafter simply referred to as a pattern cam) and a master cam 19.The barringstitch forming cam 10, the periphery of which comprising, asdescribed hereinbefore, a raisedportion 14, a recessed portion 15,protrusion 14, 15 and recessions 14", 15" provided at the starting edgeof each of the raised and lower portions in respect of the direction ofrotation of the cam 10, is mounted loosely on the cam shaft 9,

Provided adjacent the periphery of the said barringstitch forming cam 10is a cam follower means 13 having substantially the shape of the letterU in a side view, with its base portion pivotally secured to a shaft 12so as to permit its two spaced ends 13 and 13" to pivot on the shaft12.. The said U-shaped cam follower 13 carries at its upper end 13' afollower pinll for constant engagement with'the periphery of the cam 10,whereby the follower pin 11 on the upper end 13' is, upon rotation ofthe cam 10, swung outwardly or inwardly as dictated by the periphery ofthe cam 10, hence causing the other upper end 13 to swing in the sameway.

Since the upper end 13" of the U-shaped cam follower 13 is linked toaIregulator 32by means of a connecting rod 29, a bell-crank lever .30anda connecting rod 31, the swinging motion of the upper end 13" causes theregulator 32 to swing upwardly against the force of a coil spring 33having its one end secured to a part of the machine frame and its otherend secured to a part of the In this case, the amplitude of swingingmotion of the regulator 32is greater than that of swinging motion of theupper end 13, because the distance from the upper end 13" to its pivotshaft 12 is greater than that from the follower pin 11 to the shaft 12.

The said movement of the regulator 32 changes the angle of inclinationof a groove 34 provided thereon, whereby a protuberance 35 carried by abifurcated connecting rod 36 and slidably accommodated in the groove 34changes the direction of its sliding movement, imparting a swingingmotion to the bifurcated connecting rod 36 which is disposed to swingabout the protuberance 35 as its fulcrum. The movement of the rod 36 isthen transmitted to a horizontally-disposed feeding shaft connectedtherewith for automatic reversal of the direction of feeding.

The regulator 32 carries at its lower portion a protuberance 39projecting downwardly for engagement in a limiting groove 41 provided ona regulator-control cylinder 48 rotatably supported in the machineframe. The said limiting groove 41 extends radially from the centre ofthe cylinder 40, and by turning the regulator-control cylinder 40through the manipulation of a dial 42 fixed thereto externally of themachine frame, the limiting groove 41 on the control cylinder 40 isrotated to set the angle of inclination of the regulator 32 at anydesired degree to provide the desired volume of feeding. Since, however,the mechanism for adjusting the volume of feeding is the known art andthe same mechanism does not constitute an essential element in thepresent invention, a detailed explanation of this mechanism is omitted.

Provided adjacent the upper end 13" of the cam follower is an oscillatormember 45 having its base end pivotally secured to a bracket 43 by meansof a pintle 44 and carrying at its upper end a pin 46 for engagementwith one side of the upper end 13 of the cam follower 13, and engagingone side of the oscillator member 45 is an elongated pin. 47 carried ona movable arm means 24) for shifting the center-line of scam, which armmeans 20 being pivotally secured at its base end to a bracket by meansof a pintle 21. It will thus be known that the swinging motion of thecam follower 13 is transmitted not only to the feeding mechanism, asdescribed before, but also to the center-line shifting mechanism throughthe oscillator member 45, the elongated pin 47 and the movable arm means20 in the order given.

Adjacent the periphery of the barring-stitch forming cam and oppositethe location of the cam follower 13 is provided a finger-shaped switchmeans 48 pivota1ly mounted at its approximate midpoint on a shaft 49 andhaving its base end operably connected with a control lever 50 through aconnecting rod 51. Since the control lever 50 is connected with apush-button means 52 through suitable connecting members, when the edgesof the pushbutton 52 are pushed in alternatively, the control lever 51)is swung laterally, causing the switch means 48 to swing reciprocatinglyon its fulcrum shaft 49.

The finger-shaped switch means 48 carries at its upper end a hookedmember 53 and at its lower end a hooked member 53', both of which extendinwardly to face each other, and on the other hand, the barring-stitchforming cam 10 carries on one side thereof a clutch finger 16. The twoinwardly extending hooks 53 and 53 are so arranged that, when the switchmeans 48 is swung reciprocatingly on its fulcrum shaft 4-9, they moveinto or out of the path of the clutch finger 16 alternatively.

The switch means 48 also carries at its lower portion a pin 54 forengagement with the upper end of a T-shaped switch-control member 56having its base end pivotally secured to a part of the machine frame andhaving its lower end 57 constituting a follower for engagement with theperiphery of a disk 59 rigidly mounted on a shaft 58. When the disk isrotated by turning a handle 60 fixed to the outer end of the shaft 58, acut-out portion 61 on the periphery of the disk 59 is moved intoengagement with the lower end 57 and then with further rotation of thedisk 59, it is moved to disengage from the lower end 57, imparting thusa swinging motion to the T-shaped control member 56 to control themovement of the switch means 48.

Rigidly secured on the cam shaft 9 is the pattern cam 17 having on oneside thereof a clutch groove 18 into which the clutch finger. 16 carriedon the barring-stitch forming cam 10 engages periodically, and alsosecured rigidly on the cam shaft 9 adjacent the other side of thepattern cam 17 is the master cam 19. Provided adjacent the saidcenter-line shifting arm means 20 is another oscillator piece 22 havingits upper end portion pivotally secured to the movable arm means 20 at23 and carrying at its lower end a follower pin 24 for constantengagement with the periphery of the master cam 19. Under the abovearrangement, when the master cam 19 rotates, the oscillator piece 22pivots on its fulcrum point 23, imparting a 4. reciprocating motion to arod 26 engaging a protuberance 25 carried on the oscillator piece 22.The reciprocating motion of the rod 26 is then transmitted by a cranklever 27 to an L-shaped lever 28 pivotally secured at its approximatemidpoint 37 to a a part of the machine frame, whereupon the needle bar 5supported in the L-shaped lever 28 is caused to oscillate transverselyto perform zigzag sewing.

Now, regarding the position of the present improved mechanism before thestart of a button hole sewing operation, the lower end 57 of theT-shaped control member 56 has been running on the periphery of the disk59, with the upper end of the control member 56 pressing the pin 54 ofthe finger-shaped switch means 48 upwardly to hold the switch means 48in non-operative position.

Before starting a button hole sewing operation, the disk 59 is rotatedby turning the handle 60 fixed to the outer end of the shaft 58, untilthe cut-out 61 of the periphery of the disk 59 is moved to a positioncoincident with the location of the lower end 57 of the control member56, whereupon the lower end 57 falls into the cut-out 61, disengagingthe upper end of the control member 56 from the pin 54 of the switchmeans 48 whereby the machine is converted from conventional sewing tobutton hole sewmg.

With the switch means 48 shifted to its operative posirion for sewingbutton holes, the machine is set in motion. The 1st stitch of abuttonhole sewing is effected, as shown in FIGURE 8, at the uppermostend of the outer line of a zigzag seam on the left-hand side of abuttonhole (a), the 2nd stitch on the inner line, the 3rd stitch on theouter line again and so on, as led by a conventional zigzag motion,until a zigzag sewing on the lefthand side of the button hole iscompleted.

During the above sewingoperation, both the pattern cam 17 and the mastercam- 19 rigidly mounted on the common cam shaft 9 rotates with rotationof the latter, causing the oscillator piece 22 to swing reciprocatinglyon its fulcrum point 23, which reciprocating motion of the oscillatorpiece 22 being then transmitted, by the rod 26 connected thereto, thecrank lever 27 and the L-shaped lever 28, to the needle'bar 5 tooscillate the latter transversely for formation of a zigzag seam on thelefthand side of the buttonhole (a).

On the other hand, since thebarring-stitch forming cam 10 is looselymounted on the cam shaft 9, the cam 10 does not rotate with rotationofthe cam shaft 9 and is held in the standstill position, and also duringthe above sewing operation, the lower hooked member 53' carried on thefinger-shaped switch means 48 remains in the path of the clutch finger16 to press and keep the latter away from engagement with the recessedclutch means 18 provided on the pattern cam 17.

The moment a zigzag sewing on the left-hand side of the buttonhole hasbeen completed, the pushbutton 52 is pushed in to swing the controllever 50 to the opposite direction, which movement of the lever 50 istransmitted by the connecting rod 51 to the switch means 48, causing itto swing, whereupon the lower hooked member 53' is moved outwardly,disengaging itself from the clutch finger 16. At this moment, as theclutch finger 16 on the switch means 48 engages in the recessed clutchmeans 18 of the pattern cam 17, the barring-stitch forming cam 10 andthe'pattern cam 17 are connected with each other to constitute a singlefunctional unit, which then rotates with rotation of the cam shaft 9.

Now, with rotation of the barring-stitch forming cam 10, thefollower pin11 of the cam follower 13, which has been held in contact with theterminal edge of the recessed portion 15 of the periphery of the cam 10,starts moving toward the raised portion 14, and when the follower pin 11has moved up on the protrusion 14' established hi. front of the raisedportion 14 in relation to the direction of rotation of the cam 10, thecam follower 13 is swung outwardly, causin the movable arm means 20 andthe oscillator member 45 to swing outwardly. This movement of themembers 20 and 45 actuates the outward movement of the point 23 at whichthe oscillator piece 22 is pivotally secured to the movable arm means20, thereby moving the needle bar 5 outwardly to shift the neutral pointof its zigzag movement to the inner line of a zigzag seam on theopposite side, namely, on the right-hand side of thebuttonhole (a). Atthis moment, another oscillating motion is imparted to the needle bar 5by the master cam 19 through the oscillator piece 22, and this motion issynchronized with the motion actuated by the movable arm means 20 byengagement of the clutch element 16 with recess 18 as described aboveand shifts the neutral point of the needle bar 5 by the distancecorresponding to the combined amplitude of the two motions, therebyshifting the needle to the outer line of a zigzag seam on the right-handside of the buttonhole to effect the 1st stitch on the right-hand sideat that position.

At the next moment, the follower pin 11 carried on the cam follower 13falls into the recession 14", causing the cam following 13 to swinginwardly to take its original position and simultaneously, the followerpin 24 carried on the oscillator piece 22 falls into the bottom of themaster cam 19, thereby shifting the neutral point of the needle bar backto its initial position, namely, to the outer line of a zigzag seam onthe left-hand side of the buttonhole (a), where the 2nd stitch iseffected. This operation is repeated odd times as dictated by theprotrusions 14' and the recessions 14", so that barring stitches (b) inodd numbers may be produced at the lower end of the buttonhole (a).

With further rotation of the barring-stitch forming cam 10, the followerpin carried on the cam follower 13 moves up on the raised portion 14,causing the upper end 13" to swing outwardly, and while the follower pinllruns on the raised portion 14, the upper end 13" is held in thatposition, pulling upwardly the regulator 32 connected thereto throughthe linking members 29, 30 and 31 for automatic reversal of the feedingdirection. With the direction of feeding shifted backward, zigzag sewingof the right-hand side of the buttonhole (a) is effected under aconventional zigzag motion actuated by the coordinated motions of themaster cam 19 and the oscillator piece 22;

During the above sewing operation, the barring-stitch forming cam andthe clutch finger 16 carried thereon rotate, and as the clutch finger 16passes under the upper hooked member 53 which has remained in the pathof the clutch finger 16 since the time when the oppositelydisposedhooked member 53' was moved out of the path of the clutch finger 16 bymeans of the switch means 48, the upper hooked member 53 presses theclutch finger 16 to disengage the latter from the recessed clutch means18 of the pattern cam 17, thereby releasing the barringstitch formingcam 10 from engagement with the pattern cam 17 and the master cam 19. Atthis moment, the cam 10 suspends its rotation with the follower pin 11of the cam follower 13 positioned at the terminal edge of the raisedportion 14 of the cam periphery. Under such arrangement, zigzag sewingof the right-hand side of the buttonhole is continued by only aconventional zigzag motion.

The moment the zigzag sewing has been completed, the control lever isswung back to its initial position by means of pressing the push-button52, thereby causing the switch means 48 to swing back to its originalposition, whereupon the upper hooked member 53 is moved out ofengagement with the clutch finger 16 to permit the latter to engage inthe recessed clutch means 18 again, thus connecting the barring-stitchforming cam, the master cam and the pattern cam together for asynchronized rotation on the common shaft 9.

Then, with rotation of the barring-stitch cam 10, the

follower pin 11 which has been held in the standstill position at theterminal edge of the raised portion 14 starts moving toward the recessedportion 15 and when it falls into the recession 15" provided in thefront of the recessed portion 15 in relation to the direction ofrotation of the cam 10, all of the cam follower 13, the movable armmeans 20 and the pivotal point 23 of the oscillator piece 22 are movedinwardly, causing the neutral point of the zigzag movement of the needlebar 5 to shift to the inner line of zigzag seam on the left-hand side ofthe buttonhole (a). At this moment, as already described inthe case ofshifting of the needle bar from the lefthand side to the right-hand sideof the buttonhole (a), the needle bar is shifted to the outer line ofzigzag seam on the left-hand side of the buttonhole by the addedmovement of the synchronized motions of the barringstitch forming cam 10and the oscillator piece 22, where it effects a barring stitch.

At the next moment, the follower pin 11 rises up on the protrusion 15',moving the cam follower 13 outwardly, and simultaneously, the followerpin 24 carried on the oscillator piece 22 rises up the top of the mastercam 19. With the added movement of the synchronised motions, the needlebar 5 is shifted back to the outer line of zigzag seam on the right-handside of the buttonhole to effect another barring stitch. This operationis repeated odd times to effect barring stitches in odd numhere at theupper end of the buttonhole, thus completing the whole buttonhole sewingoperation.

At this moment, as the follower pin 11 on the cam follower 13 engagesthe recessed portion 15 of the periphery of the barring-stitch formingcam 10, biasing the follower 13 inwardly, the feed adjusting mechanismconnected thereto through the linking members 29, 30 and 31 is shiftedback to its forward-feeding position to prepare for the next buttonholesewing operation, with the neutral point of the needle bar positioned atthe uppermost end of the outer line of a zigzag seam on the left-handside of the next buttonhole.

In the barring-stitch operation wherein the cam follower 13 is swung oddtimes by the protrusions 14 and 15' and recessions 14" and 15", theoutward movement of the cam follower 13 causes the feed-adjustingmechanism connected therewith through'linking members to shift from theforward position to the backward position and vice versa, but since theswitch-overs of feed directions take place almost instantaneously withthe fol lower pin 11 rising up and falling down the protrusions andrecessions almost instantaneously, the cloth moves only slightly. Forthe formation of ordinary zigzag seams after the completion of thebuttonhole sewing operation, the disk 59 is rotated by turning thehandle 60, whereupon the lower end 57 of the T-shaped control member 56,which has been engaged in the cut-out 61 of the disk 59, is caused torun up on the periphery of the disk member, resulting in the upper endof the control member 56 pressing the pin 54 of the switch means 48upwardly. Then, the lower hooked member 53' of the switch member 48 iscaused to press the clutch finger 16 to disengage the latter from therecessed clutch means 13 of the pattern cam 17, thereby releasing thebarrings'titch forming cam 10 from engagement with the cam shaft 9 andholding the cam 10 in its non-operative position during the formation ofordinary zigzag seams.

As hereinbefore described, by providing conventional zigzag sewingmachines with my improved mechanism, the machines are made to performnot only zigzag sewing of various patterns but also buttonhole sewingwherein zigzag sewing of both sides of a buttonhole is effected under aconventional zigzag motion and barring stitching of the upper and lowerends of the buttonhole is effected under the coordinated motions of themaster cam and the barring-stitch forming cam.

Furthermore, since a switch-over from a conventional zigzag motion to abarring-stitch motion and vice versa can be carried out by simplypushing a pushbutton, a buttonhole sewing operation incorporatingperfect barring stitches in odd numbers will be accomplished with greatease and, further, such a switch-over can be carried out at any time andplace desired, permitting sewing of butto'nholes of various lengths.

Having thus described the nature of my invention, what I claim hereinis:

1. In a zigzag sewing machine having a transversely oscillatable needlebar, a buttonhole sewing mechanism comprising a main shaft, a cam shaftdriven by the main shaft, a master cam and a pattern cam rigidly mountedon the cam shaft, a cam for barring stitching having a periphery mountedloosely on said cam shaft at a position adjacent said pattern earn, acam follower member, the periphery of said barring-stitch forming camcomprising a raised portion to swing said cam follower member engagingtherewith outwardly for a substantial portion of a half rotation of saidearn, a recessed portion to swing said cam follower member inwardly fora similar portion of a half rotation of said cam, protrusions andrecessions provided at the starting edge of each of said raised andrecessed portions to swing said cam follower an odd number of times, afingered clutch means mounted on one side of said barring-stitch formingcam to selectively connect the latter for rotation with said cam shaft,and manually operated means to actuate said clutch means.

2. In a zigzag sewing machine having a transversely oscillatable needlebar, a buttonhole sewing mechanism comprising a main shaft, a feedadjusting mechanism for said sewing machine, a cam shaft driven by themain shaft, a master cam and a pattern cam rigidly mounted on said camshaft, a cam for barringstitching mounted loosely on said cam shaft at aposition adjacent said pattern cam, manually operated means adapted toselectively connect said cam for barring stitching to said cam shaft, acam follower member provided adjacent said barring-stitch forming cam,said cam follower member being constructed in the shape of the letter Uin side view, and having its base portion pivotally secured to a shaft,a connecting rod connecting one upper end of said U with saidfeed-adjusting mechanism, a bell-crank lever and other linking members,a follower pin carried on the other upper end of the U-shaped camfollower for constant engagement with the periphery .of saidbarring-stitch forming cam, an oscillator member provided adjacent saidcam follower, a bracket mounted in said sewing machine, said oscillatormember having its base end pivotally secured to said bracket and a pinmounted at the upper end of said bracket for engagement with one side ofsaid cam follower, a movable arm means for shifting the center line of aseam adapted for engagement with the upper side of said oscillatormember, an elongated pin carried on the upper portion thereof, saidmovable arm means having its base end pivotally mounted on said machine,another oscillator piece pivotally secured at its upper end to the upperportion of said movable arm means and a protuberance on one side of saidanother oscillator piece, a connecting rod means connected to saidanother oscillator piece by said protuberance, said connecting rod meansbeing linked at its end to the needle bar through a plurality ofsuitable linking members.

3. In a zigzag sewing machine having a transversely oscillatable needlebar, a buttonhole sewing mechanism comprising a main shaft, a cam shaftdriven by the main shaft, a master cam and a pattern cam rigidly mountedon said cam shaft, a cam for barring stitching mounted loosely on saidcam shaft, a fingered clutch means adapted to secure said cam forbarring stitching to said cam shaft, a switch means provided oppositethe periphcry of said barring-stitch forming cam and pivotally mountedat its approximate midpoint, said switch means carrying at both its endsa hooked member arranged to be moved selectively into and out of thepath of said fingered clutch means and a control lever operativelyconnected to said switch means. I

4. In a zigzag sewing machine having a shaft, a disc, a transverselyoscillatable needle bar, a buttonhole sewing mechanism comprising a mainshaft, a cam shaft driven by the main shaft, a master cam and a patterncam rigidly mounted on said cam shaft, a cam for barring stitchingmounted loosely on said cam shaft at a position adjacent said patterncam, clutch means on said cam for barring stitching adapted to engagesaid pattern cam, a switch means for disengaging said clutch meansprovided opposite the periphery of said barring-stitch forming camhaving fingers extending between said pattern cam and said cam forbarring stitching said switch means being pivotally mounted at itsapproximate midpoint, a T-shaped control means, a pin carried on saidswitch means for engagement with the upper end of said T-shaped controlmeans, said control means pivotally secured to the machine a notched,manually rotatable disc mounted on said machine, and follower meansoperatively connected to said T-shaped control means whereby, when saiddisc is rotated to bring said notch opposite said follower, said controlmeans is withdrawn from said switch means.

References Cited in the file of this patent UNITED STATES PATENTS1,675,508 Muller July 3, 1928 2,901,068 Tipper Aug. 25, 1959 2,983,240Engel May 9, 1961 3,060,875 Iida Oct. 30, 1962

1. IN A ZIGZAG SEWING MACHINE HAVING A TRANSVERSELY OSCILLATABLE NEEDLEBAR, A BUTTONHOLE SEWING MECHANISM COMPRISING A MAIN SHAFT, A CAM SHAFTDRIVEN BY THE MAIN SHAFT, A MASTER CAM AND A PATTERN CAM RIGIDLY MOUNTEDON THE CAM SHAFT, A CAM FOR BARRING STITCHING HAVING A PERIPHERY MOUNTEDLOOSELY ON SAID CAM SHAFT AT A POSITION ADJACENT SAID PATTERN CAM, A CAMFOLLOWER MEMBER, THE PERIPHERY OF SAID BARRING-STICHT FORMING CAMCOMPRISING A RAISED PORTION TO SWING SAID CAM FOLLOWER MEMBER ENGAGINGTHEREWITH OUTWARDLY FOR A SUBSTANTIAL PORTION OF A HALF ROTATION OF SAIDCAM, A RECESSED PORTION TO SWING SAID CAM FOLLOWER MEMBER INWARDLY FOR ASIMILAR PORTION OF A HALF ROTATION OF SAID CAM, PROTRUSIONS ANDRECESSIONS PROVIDED AT THE STARTING EDGE OF EACH OF SAID RAISED ANDRECESSED PORTIONS TO SWING SAID CAM FOLLOWER AN ODD NUMBER OF TIMES, AFINGERED CLUTCH MEANS MOUNTED ON ONE SIDE OF SAID BARRING-STITCH FORMINGCAM TO SELECTIVELY CONNECT THE LATTER FOR ROTATION WITH SAID CAM SHAFT,AND MANUALLY OPERATED MEANS TO ACTUATE SAID CLUTCH MEANS.